Fibre Channel is a computer communications protocol designed to meet the many requirements related to the ever increasing demand for high performance information transfer. The Fibre Channel protocol is sometimes referred to in the literature as Fiber Channel; the variation is due to differences in spelling between American English and British English. Fibre Channel combines the benefits of both channel and network technology and also provides for flexible topologies, connectivity over several kilometers (not to exceed generally 10 kilometers (km)), and support for multiple relatively high data rates, media types, and connectors. Fibre Channel has become relatively popular for connecting multiple storage devices together in a storage area network (SAN). The popularity is partly due to the fact that once a channel between two devices is set up very little decision making is needed, allowing for a high speed, hardware intensive environment.
Unfortunately, communication between and with storage area networks cannot be met with existing Fibre Channel networks. Increasingly storage area networks are becoming geographically dispersed. This dispersion is due to many factors: mergers and acquisitions of companies located nationally and internationally; desire to provide off-site storage; and storage replication, among other factors. Due to the upper limit on the distance of about 10 km between two devices on a Fibre Channel network, it is unpracticable to interconnect two storage area networks that are separated by a distance greater than 10 km using Fibre Channel.
Several solutions have been proposed for interconnecting geographically dispersed SANs. However, the proposed solutions are unsatisfactory for a variety of shortcomings. For example, the proposed solutions often involve the establishment of a non-Fibre Channel network (or point-to-point interconnect) with a proprietary protocol and hardware for transporting Fibre Channel frames over large distances (greater than 10 km). Furthermore, the solutions often involve the establishment of a network (or point-to-point interconnect) that is parallel to wide area networks (WANs) and metropolitan area networks (MANs) that communicate over large distances via standard non-proprietary protocols. Many national and international carriers operate MANs and WANs in accordance with Asynchronous Transfer Mode (ATM), Transfer Control Protocol/Internet Protocol (TCP/IP), and Synchronous Optical Network (SONET), among other protocols. These networks leverage the economy scale afforded by a large number of independent users to provide a relatively economical service. In contrast to these networks which provide a cost-effective solution for communication over large distances, the parallel network may be relatively costly, inefficient and needlessly redundant. For example, the parallel network requires separate management and maintenance effort and does not benefit from the economy of scale due to many users using the same network.
As described above, existing solutions are not capable of providing efficient, non-proprietary, and relatively economical communication between geographically dispersed SANs. Consequently, it is desirable to interconnect geographically dispersed Fibre Channel enabled SANs using the standard protocols of non-Fibre Channel networks that can provide a relatively economical and efficient solution.